Plots from northertreline-pc1.xmgr

The plotter command file "northertreline-pc1.xmgr" contains two data series, which I've labeled Northertree1 (runs from 1400-1982) and Northertree2 (runs from year 1000-1980). These data files are plotted below (I'm just showing the "hockey stick" right side of the graph).